BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Mountain Chickadee In Coastal California

All regionsCoastal CaliforniaForest birds

Mountain Chickadee in Coastal California has collapsed: down 77% on the route-weighted index since 1971.

-77%Since 1971TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
38Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Mountain Chickadee has collapsed in Coastal California: down 77% on the route-weighted index since 1971.

Mountain Chickadee In Coastal California Population Forecast

If the recent trend holds, Mountain Chickadee in Coastal California is projected to rise about 106% by 2029 — from 0.94 in 2024 to a central estimate of 1.9 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±61.2%, with 100% of held-out values landing inside the 95% band.

+106%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
1.9Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.895% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±61.2%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Mountain Chickadee in Coastal California is projected to rise about 106% by 2029 — from 0.94 in 2024 to a central estimate of 1.9 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±61.2%, with 100% of held-out values landing inside the 95% band.19692029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20252.10.004.9
20262.00.004.9
20272.00.004.8
20282.00.004.8
20291.90.004.8

Routes In Coastal California

Routes recording Mountain Chickadee in Coastal California.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
ValyermoCALIFORNIA652019
Mt LagunaCALIFORNIA381987
WoodlandsCALIFORNIA312024
Lake HemetCALIFORNIA291986
Big BearCALIFORNIA281986
FallsvaleCALIFORNIA281981
Angelus OaksCALIFORNIA212017
Yolla BollyCALIFORNIA191973
Mt PinosCALIFORNIA172004
Green ValleyCALIFORNIA132023
Sawmill MtnCALIFORNIA82013
Cleveland NfCALIFORNIA82018
StonyfordCALIFORNIA82018
White RiverCALIFORNIA71992
Lake Hemet 2CALIFORNIA62023
CohassetCALIFORNIA52024
Anza 2CALIFORNIA52024
Hough SpringsCALIFORNIA52007
Lockwood ValCALIFORNIA32018
Cuyamaca PkCALIFORNIA32023
Elizabeth LkCALIFORNIA32016
Cleveland Nf 2CALIFORNIA32022
Mt BaldyCALIFORNIA22024
Lake CachumaCALIFORNIA21987
TehamaCALIFORNIA22019

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.